Anomalous current transport in Au/low-doped n-GaAs Schottky barrier diodes at low temperatures

Abstract

The current-voltage characteristics of Au/lowdoped n-GaAs Schottky diodes were determined at various temperatures in the range of 77-300 K. The estimated zero-bias barrier height and the ideality factor assuming thermionic emission (TE) show a temperature dependence of these parameters. While the ideality factor was found to show the T 0 effect, the zero-bias barrier height was found to exhibit two different trends in the temperature ranges of 77-160 K and 160-300 K. The variation in the flat-band barrier height with temperature was found to be −(4.7 ± 0.2) × 10 4 eVK −1 , approximately equal to that of the energy band gap. The value of the Richardson constant, A * * , was found to be 0.27 A cm −2 K −2 after considering the temperature dependence of the barrier height. The estimated value of this constant suggested the possibility of an interfacial oxide between the metal and the semiconductor. Investigations suggested the possibility of a thermionic field-emission-dominated current transport with a higher characteristic energy than that predicted by the theory. The observed variation in the zero-bias barrier height and the ideality factor could be explained in terms of barrier height inhomogenities in the Schottky diode.

Interface states density distribution in Au/n-GaAs Schottky diodes on n-Ge and n-GaAs substrates

“…In an n-type semiconductor, the energy of the interface states with respect to the bottom of the conduction band at the surface of the semiconductor, E ss , is given by [17][18][19][20][21][22][23] …”

Electrical performance of conducting polymer (SPAN) grown on GaAs with different substrate orientations

“…3) Subsequently, in addition to the regions of the heterojunction with low barrier heights, the dominant barrier heights in other regions will increase with temperature and voltage bias [35,36]. Furthermore, an apparent decrease in BH and increase in ideality factor at low temperatures are due to the barrier inhomogeneity and other effects such as defects, thickness inhomogeneity and non-uniformity of the interfacial charges [30].…”

“…Furthermore, an apparent decrease in BH and increase in ideality factor at low temperatures are due to the barrier inhomogeneity and other effects such as defects, thickness inhomogeneity and non-uniformity of the interfacial charges [30].…”

“…The SBD parameters must be determined over a broad range of temperatures because the analysis of the current-voltage (I-V) characteristics of the SBD measured only at room temperature does not provide accurate information about the conduction mechanism and the barrier nature created at metal semiconductor interface in order to understand these phenomena and determine precisely the parameters of the Schottky diodes. Chand et al [29] and Hardikar et al [30] analysed the experimental currentvoltage data which revealed that there is an increase in the ideality factor and a decrease in the zero-bias barrier height with decreasing temperature. Consequently, the ideality factor and the barrier height established from forward I-V characteristics are found to be temperature dependent.…”

Temperature dependent simulation of diamond depleted Schottky PIN diodes

“…The reason behind the variation in barrier height with voltage has been widely studied. [27][28][29] Tung's model 27 attributes barrier height inhomogeneities to the non-ideal behavior of Schottky diodes. When a region of low barrier height is surrounded by high barrier regions, the low barrier region can become "pinched" off by the high barrier region.…”